Classifier



AU8 2, 1938. c. E. wUENscH 2,125,663

GLASSIFIER Filed Nov. 25. 1935 wPatented Aug. 2, 1938 UNITED STATESyPATENT oFEicE CLASSIFIER Charles Erb Wuensch, Joplin, Mo., assignor toWuensch Hetero Concentration Processi` Company, Wilmington, Del., acorporation of Dela- Ware Application November 23,1935, serial No.51,329

c claims. (cieca-17s) classification of minerals in the presence ofliquidY such as Water.

As a result of my investigations I have developed a system ofclassification whereby the density of a classified overow, its volume,and the size of the particlesl'in said overflow are controlled withinvery close limits.

Briefly my invention comprises a classifier of improved and noveldesign, as well as a novel grinding circuit in which this classifier maybe incorporated. `My invention also contemplates a novel system ofcontrol mechanism whereby the character, density, volume, etc., of theclassifier feed or the classified product may be controlled within closelimits.

The classifier of my invention comprises a tapered or conical chamberhaving its apex at the bottom, an agitating mechanism disposed centrallywithin the chamber, means for withdrawing material from the bottom ofthe chamb er, a peripheral launder around the upper part of the chamber,and means for varying the rate of withdrawal of material from the bottomportion of the chamber in response to variations in the density of thematerial in this portion.

The novel classifier circuit into which my improved classifier may beincorporated comprises a wet grinding means, means for feeding coarsematerial to the grinding means, a classifier, a conduit wherebymaterialrwithdrawn from the bottom portion of the classifier may bereturned to the grinding means, a conduit whereby material dischargedfrom the grinding means may 'be introduced into the classifier, andmeans whereby-the amount of coarse material fed to the classifier isvaried in response to variations in the density of the materialin thebottom portion of the classifier.

My invention Awill be more, completely understood if reference is had tothe accompanying drawing, in which 'Ihe figure represents a preferredapparatus of my invention.

Referring now to the figure, it will be seen that my apparatus comprisesa separating chamber l,

the bottom of which is conical in form with the apex of the cone pointeddownward. Within the separating chamber and near the upper end thereofis a concentrically disposed splash ring` 2 to prevent the disturbanceof the outer surface of liquid in the chamber.l Around the upperperiphery of the separating chamber is a launder 3, provided with anannular partition il. At the top of the annular partition is avertically adjustable Weir or overflow lip 5, which should be fastenedto the top of the launder in such manner that its top may be raised orlowered. Thus the lip may overlap the partition and be supported at itsinner portion by three or more vertically adjustable bolts dl) whichrest in brackets 4l on the innermost wall of the launder and arethreaded through the lip. By turning the bolts the lip is raised orlowered.

Centrally disposed in the chamber is a vertical hollow shaft 6 providedwith means l for revolving it,` such as a gear, at its upper end. VVAtthe lower end of the hollow shaft is a skeleton conically-shapcdagitator structure 8, of' cage-like construction. Within the cage is afloat 9 fastened to the endiof a rod l which extends upwardly throughthe hollow shaft and is provided with an insulated contact ll at itsupper end.

A ball mill l2 or other wet grinding device provided with a scoop i3 orother convenient means for introducing feed into the millis operativelyassociated with the classifier. The feed for the mill passes into a feedbox lt from a feeder chute l5 which is ordinarily in operation exceptwhen interrupted i as will hereinafter be described. Water is alsosupplied to the feed box and the mixture of water and ore is scooped upand introduced into the feed 4end of the mill. The discharge from themill is sent into the central zone of the classifier within the splashring.

A pump it is fastened to the bottom of the classifier cone and isconnected by suitable pipe line l'l to the feed b'o'x for the ballmill.'

The outer portion of the peripheral launder on the classifier isprovided with a drain to a sump it. Another pump i9 is so disposed as topump material from this sump up into a surge tank 2li into which watermay also be introduced through a oat operated valve 2l. By means of agravity flow through a pipe line 22, water, together'with solid materialfrom the surge tank, may be introduced into the classifier cone througha series of annularly disposed pipes 23 which are protected at theirdischarge ends by means of guards 2li.

In the aforementioned pipe line there is a solenoid operate-d valve 25which is actuated by'a power source 26 and opened when a hydrometer 2lplaced in the upper portion of the classifier rises so as to close apair of contacts 28, 29.

Also disposed in the upper portion of the classifier is-a float 30which, when it rises, will open a pair of contacts 32, 33 and interrupta supply of power to a motor (not shown) which drives a shaker mechanism3| for the feeder and thus interrupts the supply of feed to the ballmill.

' Also disposed within the upper portion of the classiiier is a secondhydrometer 34 which, when it rises, will close a pair of contacts 35, 36and supply power from a source 31 to open a solenoid operated valve 38on the water supply to the mill.

The pair of contacts ll on the top of the rod extending up through thehollow shaft of the classifier open when the float at the lower end ofthe rod is raised 'and thus interrupt the supply of power to the shakermechanism and speed up the pump discharging the sandy accumulations tothe feed sump of the ball. mill.

The operation of my apparatus may be described as follows:

Comminuted feed of the proper density for grinding, (say 80% solids), isdelivered from the discharge of the mill to the center of theclassifier. Within the classifier segregation takes place and due tointerrupted settling a certain amount of material overflows from theclassier through the inner launder and may be sent to flotation.

l Coarser material which will not overflow settles into the bottom ofthe cone and is there withdrawn by the pump and returned to the feeder.The cage-like structure in the bottom of the cone is continuouslyrevolved and prevents clogging. At the same time, should the density ofthe material in the bottom of the cone become too great, thus indicatingthat the grinding operation is not producing a sufliciently Ane product,the float will rise and the feed will be momentarily cut oi of the ballmill, until such time as the float again sinks. The same accumulation inthe bottom of the cone will be removed and returned to the ball millfeed box.

The density of the material overflowing from the classifier iscontrolled' by means of the hydrometer 21 which, rising, closes thecontacts 28, 29 and thus permits water to be introduced through the jets23 around the periphery of the cone. This water is also accompanied bysuch solids as overflow over the adjustable weir 5 and are passedthrough the sump I8 and the pump I9 into the surge tank 20.

As a control of the volume of the material overowing from the classifierinto the inner launder, the oat 30 is provided. If the volume at thispoint is too great, the shaker mechanism 3| will be stopped until suchtime as the amount and character of the ball mill discharge are proper.

Lastly, the hydrometer placed within the splash ring in the classiiierserves to automatically change the amount of water introducedI into themill and thus assures a proper amount of water in the ball milloverflow.

My apparatus is particularly desirable in that the classifier, evenwithout the automatic controls, permits an amazingly uniform classiiierproduct to be obtained.

When the automatic controls are also utilized, the character of theproduct becomes still further improved.

. I claim:

1. In a classifier which comprises a downwardly tapering chamber, meansfor withdrawing material respectivelyfro'm lower and upper portions ofthe chamber, and an agitator disposed in the lower portion of thechamber, the combination which comprises a cage-like agitator in thelower portion of the chamber driven from the top by an upright hollowshaft, a oat disposed within the withdrawal.

2. In a classiiler circuit comprising a settling chamber, a wet grindingmeans, means for discharging wet ground material from the grinding meansinto an upper central portion of the settling chamber, means f( rwithdrawing settled material from a lower portion of the settlingchamber and returning it to the grinding means, and means forwithdrawing unsettled material from an outer upper portion oi' thesettling chamber, the combination which comprises a hydrometer disposedin the upper central portion of the chamber, means for supplying liquidto the wet grinding means, lmeans operatively connected to thehydrometer and to the means for supplying liquid to the wet grindingmeans for increasing the amount of liquid to the wet grinding means whensaid hydrometer rises, a second hydrometer disposed in the outer upperportion oi the chamber adjacent the withdrawal means for unsettledmaterial, a plurality of conduits communicating with the settlingchamber at points intermediate the top and bottom thereof, means vforintroducing water into the settling chamber through said conduits whensaid second hydrometer rises, means operatively connecting said secondhydrometer and the means for introducing water into the settlingchamber.

3. In a classifier circuit comprising a settling chamber, a wet grindingmeans, means for discharging wet ground material from the grinding meansinto an upper central portion of the settlingl chamber, means forwithdrawing settled material from a lower portion of the chamber andreturning it to the wet grinding means, and means for withdrawingunsettled material from an upper outer portion of the settling chamber,the combination which comprises a hydrometer disposed in the uppercentral portion of the chamber, means for increasing the amount of waterintroduced into the grinding means when the hydrometer rises, meansoperatively connecting the hydrometer and the means for increasing theamount of water introduced into the grinding means, a second hydrometerdisposed in the upper outer portion of the chamber, means for admittingwater into the chamber at a plurality of points .intermediate the topand bottom thereof, means for increasing the amount of water admitted atsaid points when the second hydrometer rises, a float disposed in alower portion'of the chamber, means for reducing in response to a riseof said iioat the amount of fresh solid feed to the grinding means andincreasing the amount of settled material withdrawn from the chamber andreturned to the grinding'means and means operatively connecting saidiloat to said means for reducing the amount of fresh solid feed andincreasing the amount of settled material withdrawn.

' '4. In a classiiier which comprises a chamber,

means for introducing material to be classified into the chamber andmeans for withdrawing classied material respectively from lower andupper portions of the chamber, the improvement which comprises anoverflow for liquid disposed above the means for withdrawing classiedmaterial from the upper portion of the chamber, a tank positioned abovethe classiiier, means for introducing the liquid overflow into saidtank, a conduit for conducting the liquid from the tank to an vinletpositioned in the classiiier between the upper and lower withdrawalmeans, a hydrometer disposed in the chamber adjacent the overiiow,closure means disposed in the conduit and means operatively connectedwith the hydrometer and the closure means for opening the closure meanswhen the hydrometerrises.

5. Apparatus according to claim 4 provided with a conduit forintroducing additional liquid into said tank, a closure means disposedVin said conduit, a oat disposed in said tank and means operativelyconnected with the float and the ciosure means for closing the closuremeans when the float rises.

6. In a classiiier which comprises a chamber i for retaining solids andliquids, means for introducing solids to be classified into the chamberand means for withdrawing classied solids respectively from lower andupper portions of the chambery, the improvement which comprises anoveriiow for liquid disposed above the means fory withdrawingclassifledsolids from the -upper portion of the chamber, storage meansfor said liquid overflow, a conduit for conducting the overiiow intosaid storage means, an inlet positioned in the classifier between theupper and lower means for withdrawing classiiied solids, a conduit forconducting the overow liquid from the storage means to the inlet, ahydrometer disposed in the chamber adjacent'the overflow, closure meansdisposed in the conduit leading vfrom the storage means to the inlet andmeans operatively connected with the hydrometer and with` the closuremeans for opening the closure means when the hydrometer rises.

CHARLES ERB WUENSCH.

